Field of the Invention
The present invention generally relates to a hydraulic valve lash adjuster for a vehicle. More particularly, the present invention relates to a valve lash adjuster for a diesel engine, such as a commercial diesel engine, having high power and a large engine displacement.
Description of Related Art
In general, an engine has a valve opening/closing mechanism enabling the operation of intake and exhaust valves using a crank shaft rotating following a piston motion. Such a valve opening/closing mechanism includes a cam shaft connected to the crank shaft by means of a belt to cooperate with the crank shaft, rocker arms rocking within a set range in response to the cam shaft, and intake and exhaust valves allowing the passage of mixture gas and exhaust gas through close contact with the rocker arms. In particular, since the heads of the intake and exhaust valves are exposed to the interior of a combustion chamber, the intake and exhaust valves expand with combustion heat applied thereto. For this, a hydraulic lash adjuster (HLA) adjusts the lash between the intake/exhaust valve and the rocker arm by considering the coefficient of expansion such that the lash between the intake/exhaust valve and the rocker arm is constantly set to “0.” In a valve train system provided with such an HLA, the intake value or the exhaust valve opens and closes an intake port or an exhaust port while moving up and down in response to the knob of a cam pressing a rocker arm while rotating about the cam shaft. The HLA is disposed on one end of the rocker arm to adjust the valve lash while varying the height at which the rocker arm contacts the valve.
However, it is difficult to apply such an HLA to a commercial diesel engine having high power and a large engine displacement, due to the size of the HLA.
The information disclosed in the Background of the Invention section is only for the enhancement of understanding of the background of the invention, and should not be taken as an acknowledgment or as any form of suggestion that this information forms a prior art that would already be known to a person skilled in the art.